Method and apparatus for forming spiral pipe



J. E. FAY 3,287,536

METHOD AND APPARATUS FOR FORMING SPIRAL PIPE Nov. 22, 1966 6 Sheets-Sheet l Filed March 24. 1965 INVENTOR.

E. FAY

6 Sheets-Sheet 2 JAMES ATTORNEYS J. E. FAY

Nov. 22, 1966 METHOD AND APPARATUS FOR FORMING SPIRAL PIPE Filed March 24, 1965 J. E. FAY

Nov. 2z, 1966 A METHOD AND APPARATUS FOR FORMING SPIRAL PIPE 6 Sheets-Sheet 5 Filed March 24, 1965 ATTORNEYS J. E. FAY 3,287,536

METHOD AND APPARATUS FOR FORMING SPIRAL PIPE Nov. 22, 1966 6 Sheets-Sheet 4.

Filed March 24, 1965 FIG. 8

INVENTOR. JAMES E. FAY Bfnu Eff/Mr /Wm- 7:7/0/41/0 ATTORNEYS Nov. 22, 1966 J. E. FAY 3,287,536

METHOD AND APPARATUS FOR FORMING SPIRAL PIPE Filed March 24, 1965 6 Sheets-Sheet 5 FIG. 10

1N VEN TOR. JAMES E. PAY

'SYM EMM/@Eh www ATTORNEYS J. E. FAY 3,287,536

METHOD AND APPARATUS FOR FORMING SPIRAL PIPE Nov. 22, 1966 6 Sheets-Sheet 6 Filed March 24, 1965 INVENTOR. J'A M ES E. FAY

im aM/y 14W 7,7/4 ww ATTORNEYS United States Patent O 3,287,536 METHOD AND APPARATUS FOR FORMING SPIRAL PIPE James E. Fay, Middletown, Ohio, assignor to Fay Pipe and Pile Co., Inc., Pittsburgh, Pa., a corporation of Pennsylvania Filed Mar. Z4, 1965, Ser. No. 442,391 9 Claims. (Cl. 219--62) This invention relates to the continuous formation of pipe and more particularly relates to a novel method and apparatus for continuously manufacturing pipe from a sheet material in which the sheet material is formed into a spiral and the edges of the spiral are joined by forging.

Prior methods for continuously forming pipe have included the formation of straight-seam pipe by bending a substantially rectangular strip of sheet material into a cylindrical shape and .then securing the seam by welding or Iother edge joining techniques. Bending of the strip into a cylindrical shape has been accomplished by drawing the strip through a restrictive circular opening or die. Edge joining techniques used in the production of straight-seam pipe have included fusing edges together by first heating the edges, moving them into abutting relationship and then applying forces in a direction substantially parallel to the plane of .the surface of the cylinder at the area 'of contact of the edges to accomplish a fusion of the heated edges. While this method has been widely used to form straight-seam pipe, the method has several drawbacks. v

Pipe formed by this prior method has a longitudinal axis which does not follow a straight line. The reason for this is that the weld of the seam shrinks thus causing the pipe to bow, and therefore straight-seam pipe made in this manner must be straightened to be acceptable for many uses. Another reason for the bowing or bending of the pipe formed by this prior method is that the forces used to join the edges cause variations in the -pipe diameter because the effective width of the sheet material is reduced by the squeezing together of the .heated edges.

A second disadvantage of this prior method is the limitation in the number of different diameters of the pipe that can be formed on the apparatus used in practicing the method` In order to change the diameter of the pipe :to be formed, the apparatus rnust be disassembled to substitute a new die. This is required because each circular die opening of the apparatus has a fixed diameter and therefore only piperof that diameter can be formed thereon. v

Prior methodsA of forming spiral pipe using forging techniques to join the sheet edges also have important limitations. In the operation of conventional spiral forming techniques, the edges of the sheet material contact one another in advance of the point where the spiral forming is completed. The point Where the edges first contact one another in the conventional formation of spiral pipe is referred to herein as vthe contact or tangent point. Since the sheet edges are heated to a plastic state prior to their contact or tangent point, the edges are subjected .to a shearing action as they move relative to one another through the distance starting with the contact point and ending when they reach the point where the spiral formation is complete. This period of shearing action of the plastic edges prevents formation of a satisfactory juncture or union of the edges,

The present invention is directed to overcoming this drawback in the formation of spiral pipe. It should be noted that conventional spiral forming methods use forming units which are adjustable to ensure that the spiral formed has contacting and therefore shearing edges as herein described.

Unlike conventionally formed spiral loop, the forming technique of the present invention forms a spiral loop in such a way that the edges in advance of the edge joining or juncture position do not contact one another prior to .the complete formation of the spiral. Instead the edges first come together in the vertical plane where the spiral loop is formed into the completed pipe.

The novel method and apparatus of the present invention overcomes these disadvantages of prior methods in that the invention provides for means of produc-ing straight pipe of selected diameters which have superior edge junctures.

Broadly the present invention comprises feeding a sheet material into a sheet working unit adapted to form a deformed spiral loop having its advanced edges -in a generally opposing and spaced-apart relationship and then feeding the deformed loop into a reforming and joining unit to reform the loop and edges using press forging techniques.

Apparatus used in practicing the invention employs reforming and joining means which include means for heating the spiral loop edges in advance of the edge joining or juncture position by using high-frequency electrical current, press forging means and a circumference control device.

In the practice of the present invention, a deformed spiral loop is formed either by ilanging the edges of the sheet material of the loop or, alternatively, by forming a loop in which the edges are not flanged but in which the configuration of spiral loop is deformed in such a way that the advanced edges of the loop are held in generally opposed and spaced-apart relationship. Either a spiral loop of the configuration that would be formed for the manufacture of conventional pipe of the selected diameter may first be formed and then distorted to spread apart the edges of the spiral loop, or the forming unit 'may be adjusted to form in the first instance a deformed spiral loop. In the production of conventional spiral loops used in the manufacture of spiral pipe, the width of the sheet material, the angle of feed of the material into the forming unit and the dimensions of the fonming unit deteimine the diameter of the pipe produced. By varying these factors, pipe of varying diameters may be produced. As

hereafter described, these fundamental variables in the production of spiral pipe will be called the standard settings, In producing a deformed spiral lo-op in accordance with this invention, standard setting are used. Deforming the spiral loop is accomplished while `the sheet material is in the sheet working unit of my apparatus. Deformation of the spiral loop is removed during its passage into and through the reforming and joining unit of my apparatus. As is further described deformation is corrected by circumference control ring or by press forging rolls to produce a straight pipe. The purpose of the deformation in my invention is t-o maintain spaced relationship of the advanced edges of the spiral loop to prevent 'contacting of the edges prior .to the completion of the forming of the spiral pipe.

The advanced sheet edges may be maintained spaced apart by deforming through anging the edges of the sheet prior to the formation of the spiral loop. This method of deformation reduces the effective sheet width of the spiral loop as it is formed and travels to Ithe reforming and joining means. In the reforming and joining means the anges are squeezed back into the sheet to restore the sheet to lits original width.

Alternatively, the advanced edges may be maintained spaced apart by deforming the spiral loop itself through operation of the spiral forming unit. In the practice of this embodiment, the portion of deformed loop irnmediately in advance of the edge joining means is straightened by the edge joining means to permit the formation of straight pipe.

A feature of my invention is that the sheet edges are heated using high-frequency electrical current; for example, frequencies of approxiamtely 450,000- oycles per second. Commercially available high-frequency equipment may be used in the practice of my invention. It is preferred that the electrical edge contacts be mounted as close to the juncture position as possible so that the heat generated in the sheet edges by the high-frequency current is not dissipated before the edges reach the juncture position.

Another feature of my invention is the arrangement whereby the circumference control device positioned at the juncture position may be adjusted to accommodate for the movement of the juncture position. This movement of the control device permits the formation f various diameters of pipe on my apparatus. In the operation of my apparatus it is important that the control device be positioned in the vertical plane which includes the juncture position of the forming pipe and it is also necessary that the forging rollers be similarly adjustable. The location of the juncture position varies in relationship to the fixed forming knee and the pivot point of the forming unit as the diameter of pipe being produced varies. In producing a small diameter pipe, the point is located closer to a vertical plane through the pivot point than it is in the production of larger diameter pipes. The tangent point also moves within planes perpendicular to the axis of the formed pipe. My arrangement for moving the control device and the forging rollers to various positions around the forming pipe permits the formation of a wide range of pipe sizes on my apparatus.

Reference is made to the accompanying drawings which illustrate embodiments of my invention, in which:

FIG. 1 is a side elevation view of the pipe forming apparatus including the forming unit (with a portion of the front forming roll removed to show the position of the back forming roll), the spiral of sheet material, the reforming and joining unit and the press forging rollers;

FIG. 2 is a plan view illustrating a spiral loop deformed by adjusting one of the forming rolls of the forming unit;

FIG. 3 is a plan View illustrating a spiral loop deformed by an adjustable shoe;

FIG. 4 is a partial sectional view taken along line 4--4 of FIG. 9 illustrating a flange formed on the sheet edge before it is formed into a spiral;

FIG. 5 is a partial sectional view taken along line 5--5 of FIG. 3 showing the electrical contacts in contact with the anged edges of the sheet;

FIG. 6 is a partial sectional view illustrating the press forging rolls shaped to form a reinforced seam;

FIG. 7 is an alternative embodiment of the press forging rolls shaped to form a smooth pipe seam;

FIG. 8 is a sectional elevation view taken through the circumference control ring of the apparatus;

' FIG. 9 is a plan view of the sheet driving rolls and the tlanging unit;

FIG. 10 is an enlarged vsectional View taken along line l 10--10 of FIG. 9;

FIG. 11 is a partial sectional view taken along line 11-11 of FIG. 8;

FIG. 12-is an elevation view of lower press forging roll mounted on the end of the arbor of the forming unit;

FIG. 13 is a plan view showing the pivotable arm on which the lower press forging roll is mounted;

FIG. 14 is a side elevation view of an alternative A embodiment of the apparatus illustrating means for the advanced ed-ges of the deformed spiral loop;

FIG. 15 is a sectional view taken along line 15-15 of FIG. 14;

FIG. 16 is a plan view of the flanged edges as they come together and are joined by the press forging roll;

FIG. 17 is a sectional elevation view showing the press forging rollers joining the flanged sheet edges.

Referring to the drawings in detail and in particular to FIGS. l, 2, 3 and 9, it is seen that sheet material 1 is continuously fed into sheet working unit 2 by drive rolls 3 (FIG. 9). Sheet working unit 2 includes flanging unit 4 (FIG. 9) and forming unit 5. Drive rolls 3 and hanging unit 4 are mounted on carriage 6 which is pivotable about pivot point 7. Carriage 6 is` pivoted to vary the angle at which the sheet material is fed into the forming unit. Forming unit 5 includes base 8 having vertical support 9 which carries arbor 11. Stantions 13 which are also mounted on base 8 support through adjustable means (not shown) front and back forming rolls 15 and 17, respectively. Forming unit 5 may alternatively include adjustable shoe 18 mounted through mounting block 19 on stantion 13.

In FIGS. 1 and 2, the sheet material 1 has been formed in a deformed funnel-shaped spiral loop 21 by adjusting back forming roll 17. Back forming roll 17 is adjusted so that one of its ends is moved away from the line of contact in the forming spiral loop 21 to permit the forming loop 21 to move toward the back of the forming unit thus opening up a V-shaped configuration 22 as formed by advanced edges 25 and 27.

In FIG. 3, the deformed loop is formed by adjustable shoe 18. In the operation of the apparatus, the deformed spiral loop is continuously formed and is continuously fed into the reforming and joining unit 23 wherein the deformed spiral loop is reformed and its edges joined to form pipe 24. The upper and lower edges of the deformed spiral loops 25 and 27, respectively, immediately in advance of their reaching the juncture position, are herein referred to as the advanced edges of the loop.

Edges 25 and 27 are heated by high-frequency electrical unit 31 having electrical contact shoes 33 and 35 mounted for urging engagement with edges l25 and 27, respectively. The enga-gement of contacts 33y and 35 cause a high frequency cur-rent to flow through the edges and across the juncture position where the edges are than edge flanging is used. Ring 43 cooperates with device 41 to form loop deformation other than anging.

The circumference of the spiral loop as it is fed into the reforming and joining unit is maintained by circumference control device 41.

Directing attention in particular to FIG. 8, it is seen that circumference control device 41 includes frame ring 47 and adjustable radially positioned holding roller units 49. Device 41 is mounted on four (4) horizontal supports 51. Device 41 may also be partially rotated in a plane perpendicular to the axis of the formed pipe and the device is adjustable along horizontal supports 51. These adjustments permit the upper press forging roller 37 which is carried on device 41 to be moved to positions directly over the juncture positions of the edges, which position depends on the size pipe made as described above.

In FIG. 5, contact shoes 33 and 35 are shown in contact with the sheet edges at the V-shaped configuration 22 formed by the advanced sheet edges (FIG. 3).

In FIG. 6, upper and lower press forging rolls 37 and 39, respectively, are shown press forging the plasticized flanges of entering sheets together by squeezing a portion of material back into the sheet and FIG. 7 an alternative embodiment of the forging rolls is seen in which the rollers are shaped to conform with the curvature of the spiral loop.

Turning to FIGS. 9 and 10, it is seen that flange forming unit 4 includes swivel links 69 mounted on the carriage 6 (not shown). Roller boxes 71 which are pivotably mounted on links 69 each carry a series of flange forming rollers 65. Threaded tension rod 73 ties the two roller boxes together through threaded swivel nuts 75. Swivel nuts 75 are secured to boxes 71 in a position such that the tensioning of rod 73 causes the boxes to swing toward one another at angles such that the width of sheet material 1 is reduced in stages to form a flange of desired size and shape on each sheet edge.

FIG. l1 illustrates the manner in which holding roller units 49 are mounted in ring slot openings 76 so that the roller units are readily positioned in proper radial orientation and easily released from the engagement with the exterior of the formed spiral. Referring to FIG. 8 and FIG. 1l, each roller unit 49 includes fork 77 which has roller 79 journalled therein, and a threaded radial stem 83 which is mounted on fork 77 and has handle 81. Plates 85 have threaded holes therein for receiving stems 83 and lock nuts 87 are used to prevent the plates from rotating when the stem is radially adjusted. Roller units 49 maintain a selected circumference of the spiral loop thus preventing the press forging rolls from expanding the spiral as they squeeze the plasticized material in the flanges back into the sheet edges.

In FIGS. 12 and 13 swivel arm 63 is shown mounted on arbor extension 89 through swivel bolt 91. Plate 63 has slot 93 which carries roller holder 95 and bolt and washer sets 97. Upper and lower forging rollers are preferably insulated from their mountings so that highfrequency current will not be lost through the press forging rollers. The rollers are also preferably water cooled to prevent overheating.

In FIG. 14, upper edge bender unit 97 is mounted on arm 99 which is in turn attached to santion 13. Lower edge bending unit 101 is connected to stantion 13 through chain 103.

In FIG. 15, edge bender units include pairs of bending rollers 105. The sheet edges of deformed spiral loop in FIGS. 14 and 15 have flanges 66. Edges bent by the edge benders are straightened by the press forging rollers.

In FIGS. 16 and 17, flanged edges 66 are press forged by press forging roller. Contact shoes 33 and 35 are also shown.

In the practice of my invention, a roll of commercial grade sheet material is positioned on carriage 6. The angle of feed of the sheet material into the forming unit is determined by swinging carriage 6 around pivot point 7. It is preferred that the acute angle between the sheet and the forming rolls be in the range of to 30 degrees. Forming rolls and 17 of the forming unit are adjusted and if the sheet edges are to be anged the flange forming unit 4 is placed in operation by adjusting tie rod 73. The reforming and joining unit 23, including circumference control device 41 is adjusted to form a pipe of selected diameter.

Where deformation of the spiral loop is accomplished by using the forming unit, the back forming roll 17 or the adjustable shoe 18 is adjusted to control the spiral loop in such a manner that the space -between the opposing edges of the sheet in advance of the juncture position is increased to prevent premature fusing of the edges. Edge benders may also be used if desired to further deform the loop and further spread the advanced edges apart.

When the spiral loop is deformed by Hanging its edges the following steps may be taken in setting up and starting the continuous formation of the pipe. The sheet material is fed into the sheet working unit and thedeformed spiral loop then moves into the reforming and joining unit where the edges are press forged together. The circumference control ring is adjusted to bring the advanced edges together. The driving rolls are then stopped and the advanced edges are Welded together at the tangent point using any suitable welding technique. The reason for forming this initial weld is to provide a circuit for the electric current between the contacts positioned on the sheet edges. Once this circuit is formed, the high frequency current will heat the edges to plasticize them and the forging rolls are then ready to start their edge joining function. The machine is then started up and the circumference control device expanded to provide for the formation of pipe of ka desired diameter and having the desired amount of reinforcing in its seam.

When the edges are flanged the control device may be adjusted to permit the circumference of the pipe to expand under the pressure of the forging to form pipe having a smooth seam without reinforcing material in it. By reducing the circumference of the .control ring, all the material in the flanges cannot be squeezed back into the sheet because there isnt SufB-cient space between the edges as they reach the edge joining unit. In this situation, the material not squeezed back into the sheet forms a reinforced seam (F-IG. 6). Since in the practice of my invention flanges of various configurations may be used, the shape and size of the reinforced seam will vary with the size and shape of the edge flanges used.

It is understood that the term pipe, as used herein, is intended to include tubing and other similarly shaped products.

yI claim:

1. A method for continuously producing spiral pipe from a sheet material comprising,

(a) feeding the sheet material into a sheet working unit adapted to form a deformed spiral loop;

(b) forming a deforme-d spiral loop having its advanced edges held in a spaced-apart relationship due to the deformation of the loop;

(c) heating the advanced edges of the deformed spiral lioop;

(d) feeding the deformed spiral loop having its advanced edges heated into a reforming and joining unit capable of reforming the deformed loop `and joining its edges together;

(e) reforming the deformed loop as it is fed into the reforming joining means;

(f) joining the advanced edges of the spiral loop before said edges have passed through the vertical plane which passes through the center line of the spiral pipe being formed, said joining being accomplished by press forging wherein forces are applied to the edges in directions substantially perpendicular to the surface of the spiral loop, and

(g) controlling the circumference of the spiral loop as it is reformed and its edges are joined,

whereby a spiral pipe is continuously formed.

2. The method of claim 1 wherein the step of forming a deformed spiral loop includes feeding the sheet material into a spiral forming unit adapted to form a deformed spiral loop.

3. An apparatus for continuously producing spiral pipe from a sheet material comprising,

(a) a sheet working unit for forming the sheet material into a deformed spiral loop having its advanced edges held apart due to said deformation;

(b) means for driving the sheet material into the sheet working unit to form a deformed spiral loop;

(c) reforming and joining means for reforming the deformed spiral loop positioned to join its edges before they pass through the center line of the spiral pipe being formed, said reforming and joining means in turn comprising,

(1) high-frequency current heating means fo-r heating the edges just prior to their entry into reforming and joining means,

(2) press :forging means for forging the heated edges together,

(3) a circumference control device for oontrolling the circumference of the reformed loop during the operation of the forging means.

4. The apparatus of claim 3 wherein the high-frequency heating means for heating the advanced edges of the deformed spiral loop comprises a pair of electrical contacts mounted for contact with the edges of the deformed spiral loop, a source of high-frequency electrical current connected between said contacts whereby a heat-producing high-frequency electrical current is caused to flow through said edges of the deformed spiral loop.

5. A method for continuously producing spiral pipe from a sheet material comprising,

(a) feeding the sheet material into a sheet Working unit adapted to form a deformed spiral loop,

(b) forming a deformed spiral loop by Hanging at least an edge of the sheet material and forming the flanged edge sheet into a spiral loop having its advanced edges held in a spaced-apart relationship due to the flanged deformation of the loop,

(c) heating the advanced edges of the ldeformed spiral loop,

(d) feeding the deformed spi-ral loop having its advanced edges heated into a reforming and joining unit capable of reforming the deformed loop and joining its edges together,

(e) reforming the deformed loop as it is fed into the reforming joining means,

(f) joining the advanced edges of the spiral loop by press forging wherein forces are applied to the edges in directions substantially perpendicular to the surface of the spiral loop, and

(g) controlling the circumference of the spiral loop as it is reformed and its edges .are joined,

whereby a spiral pipe is continuously formed.

6. The method of claim 5 wherein the circumference of the spinal loop is controlled to form a reinforced juncture of the sheet edges as the flanged edges are press forged together.

7. An apparatus for continuously producing spiral pipe from a sheet material comprising,

(a) a sheet working unit for forming the sheet material into a deformed spiral loop having its advanced edges held apart due to said deformation, the sheet working unit comprising flanging means for applying pressure to an edge of the sheet material to form a flange thereon,

(b) means for driving the sheet material into the sheet working unit to form a deformed spiral loop,

(c) an adjustably mounted reforming and joining means for reforming the deformed spiral loop and joining its edges, said reforming and joining means in turn comprising,

(l) high-frequency current heating means for heating the edges just prior to their entry into the reforming :and joining means,

(2) press forging means for forging the heated edges together,

( 3) a circumference control device for controlling the circumference of the reformed loop during the operation of the forging means.

8. The apparatus of claim 7 wherein the sheet working unit in addition comprises la spiral forming unit having a lixed forming knee and atleast one yadjustable forming element whereby the configuration of the formed loop may be deformed by adjusting -said adjustable forming element.

9. The apparatus of claim 8 having in yaddition means for bending the advanced edges of the sheet prior to their reaching the reforming and joining means whereby the distance between said opposing edges is increased.

References Cited by the Examiner UNITED STATES PATENTS Morris 219--62 RICHARD M. WOOD, Primary Examiner. I 

1. A METHOD FOR CONTINUOUSLY PRODUCING SPIRAL PIPE FROM A SHEET MATERIAL COMPRISING, (A) FEEDING THE SHEET MATERIAL INTO A SHEET WORKING UNIT ADAPTED TO FORM A DEFORMED SPIRAL LOOP; (B) FORMING A DEFORMED SPIRAL LOOP HAVING ITS ADVANCED EDGES HELD IN A SPACED-APART RELATIONSHIP DUE TO THE DEFORMATION OF THE LOOP; (C) HEATING THE ADVANCED EDGES OF THE DEFORMED SPIRAL LOOP; (D) FEEDING THE DEFORMED SPIRAL LOOP HAVING ITS ADVANCED EDGES HEATED INTO A REFORMING AND JOINING UNIT CAPABLE OF REFORMING THE DEFORMED LOOP AND JOINING ITS EDGES TOGETHER; (E) REFORMING THE DEFORMED LOOP AS IT IS FED INTO THE REFORMING JOINING MEANS; 